<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>intersectionBy</title>
</head>

<body>
    <div>打开浏览器控制台查看结果</div>
    <script>
        const intersectionBy = (a, b, handler) => {
            const s = new Set(b.map(handler));
            return [...new Set(a)].filter(x => s.has(handler(x)));
        };
        console.log(intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor));
    </script>
</body>

</html>